Add support for ASAN-specific test expectations to WebGL tests.

testing/buildbot/chromium.gpu.fyi.json

 {
   "AAAAA1 AUTOGENERATED FILE DO NOT EDIT": {},
   "AAAAA2 See generate_buildbot_json.py to make changes": {},
   "Android Release (Nexus 5)": {
     "gtest_tests": [
       {
         "override_isolate_target": "angle_unittests",
         "swarming": {
           "can_use_on_swarming_builders": true,
           "cipd_packages": [
@@ skipping 9209 matching lines @@
         }
       },
       {
         "args": [
           "webgl_conformance",
           "--show-stdout",
           "--browser=release",
           "-v",
           "--extra-browser-args=--enable-logging=stderr --js-flags=--expose-gc",
           "--webgl-conformance-version=2.0.1",
-          "--read-abbreviated-json-results-from=../../content/test/data/gpu/webgl2_conformance_tests_output.json"
+          "--read-abbreviated-json-results-from=../../content/test/data/gpu/webgl2_conformance_tests_output.json",
+          "--is-asan"
         ],
         "isolate_name": "telemetry_gpu_integration_test",
         "name": "webgl2_conformance_tests",
         "override_compile_targets": [
           "telemetry_gpu_integration_test_run"
         ],
         "swarming": {
           "can_use_on_swarming_builders": true,
           "dimension_sets": [
             {
               "gpu": "8086:0a2e",
               "os": "Mac-10.12"
             },
             {
               "gpu": "1002:6821",
               "hidpi": "1",
               "os": "Mac"
             }
           ],
           "shards": 15
         }
       },
       {
         "args": [
           "webgl_conformance",
           "--show-stdout",
           "--browser=release",
           "-v",
-          "--extra-browser-args=--enable-logging=stderr --js-flags=--expose-gc"
+          "--extra-browser-args=--enable-logging=stderr --js-flags=--expose-gc",
+          "--is-asan"
         ],
         "isolate_name": "telemetry_gpu_integration_test",
         "name": "webgl_conformance_tests",
         "override_compile_targets": [
           "telemetry_gpu_integration_test_run"
         ],
         "swarming": {
           "can_use_on_swarming_builders": true,
           "dimension_sets": [
             {
@@ skipping 8986 matching lines @@
             {
               "gpu": "10de:104a",
               "os": "Windows-2008ServerR2-SP1"
             }
           ]
         }
       }
     ]
   }
 }